The phenomenon of inductive coupling permits contactless energy transfer between a transmitting device and a receiving device and may be supplemented with primary coil and secondary coil to form a transformer. Examples of such systems are described in WO 98/15069 A1, EP 1 885 085 A1, DE 10 2007 060 811 A1, and DE 10 2007 061 610 B4. When the devices are coupled, a closed magnetic core is formed or only small air gaps in the core are permitted so that the contactless energy transmission is very efficient. However, this requires precise spatial positioning of primary coil relative to secondary coil, which sharply limits the freedom in spatial positioning for the primary transmitting device to the secondary transmitting device.
To be relieved of this limitation in spatial positioning, U.S. Pat. No. 7,262,700 B2 and US 2010/0328044 A1 suggest arranging on a desk surface of the transmitting device flat coils, as primary coils, that cooperate with secondary flat coils of the receiving device to supply the latter with power. The receiving device with the secondary coil is mobile and may be supplied with power at any position on the desk plate of the transmitting device, wherein the transmitting device scans for where the receiving device is located so that the primary coil is operated only there. The effective magnetic field lines between primary coil and secondary coil run perpendicular to the desk surface.
U.S. Pat. No. 6,803,744 B1 relates to an inductive energy transfer device for recharging the battery of cordless devices. Below the table surface, a table houses arrangements of primary coils that may be turned on via switches and that cooperate with secondary coils of the devices to be recharged. The devices to be recharged are a laptop computer and a cordless drill that obviously may be used for its intended purpose after recharging.
Known from EP 2 067 148 B1 is a transmitting device having a rail-like charging fixture for transferring electromagnetic energy to a plurality of electronic devices, and specifically a plurality of overlapping flat primary coils are provided along a rail of the transmitting device, which coils detect the presence of a receiving device by means of a sensor and selectively activate primary coils accordingly. The effective magnetic field lines between primary coil and secondary coil run perpendicular to the rail surface.
US 2003/0210106 A1 discloses a system of inductive coupling between a plate-like primary side of the transmitting device and a secondary side of the receiving device. The primary side has a flat winding in which the windings run in a helical or rectangular shape nested within one another to permit via a desk surface inductive coupling with the receiving device, whose position and orientation within an active area of the desk surface may be freely selected. The magnetic field lines run essentially parallel to the desk surface in this active area. The secondary side has a winding about a plate-like or cylindrical core.
Known from WO2010/125048 A1 is a system for supplying bus subscriber modules with contactless energy and data, which system includes within a hat-shaped carrier-rail a power supply rail that has an energy transfer interface and a data transfer interface and each of the bus subscriber modules has a corresponding energy transfer interface and a corresponding data transfer interface. The interfaces work based on spiral flat coils whose planes run parallel to one another so that the field lines extend vertical to the longitudinal extension of the carrier rail.
US 2002/0021226 A1 relates to an electrical apparatus having a monitoring device, support, and monitoring device for such an apparatus, and electrical installation incorporating them. A switchgear housing with support rails is provided for receiving electrical apparatus, each of which apparatus has a receiving coil. In a first configuration there are transmitting coils on the front sides of the switchgear housing in which two rails with attached apparatus extend, in a second configuration there is a transmitting coil parallel to two rails on which the electrical apparatus are arranged, and in a third configuration there are top hat rails, and a single flattened coil extends in the interior of each of these, thus supplying energy to a series of electrical apparatus placed on the top hat rails. It is not possible to allocate individual transmitting coils to individual receiving coils.
Electronic devices are often accommodated in switchgear cabinets and are frequently placed along retaining rails. Often a galvanic separation is required between the power supply and the user or end devices. Although such user or end devices are adapted to the retaining rail at their base, there are significant differences with respect to the longitudinal dimensioning of the rails. With narrow devices, the surface opposing the retaining rails is quite small so that inductive coupling between the power supply and the user or end device seems problematic.